Always ask will prompt you each time you use a mail function for which program or service to use.

Use <Program> (default) will automatically launch your operating system's e-mail program (e.g. Thunderbird, Windows Live Mail, Outlook, Evolution, KMail) to its message composition window. For instructions on how to change your operating system's default e-mail program, see the next section of this article.

Use <Webmail> will open your webmail service's (e.g. Yahoo! Mail, Gmail, Hotmail) message composition page inside Firefox. For more information about using webmail services, see the Using webmail services section of this article.

Use other... will let you specify an external program for Firefox to launch.

Application Details... will let you view information about or remove the webmail services that Firefox can use.

Close the about:preferences page. Any changes you've made will automatically be saved.

Setting your operating system's default mail program

By default, Firefox will use your system's default mail client to send e-mail for the actions listed above. To change the default mail client using your operating system, follow the instructions below.

Windows 7 and Vista

Click the Start button, then click the Default Programs item.

Click on Set your default programs.

Under Programs, click the e‑mail program you'd like to use (e.g. Thunderbird, Windows Live Mail, Outlook).

Click Set this program as default.

Click OK at the bottom of the window.

Windows XP

Click the Start button, then click on the Control Panel icon to open the Windows Control Panel.

Click the Add or Remove Programs icon to open the Add or Remove Programs applet.

On the left side of the Window click the Set Program Access and Defaults icon.

In the Access and Defaults window, click on the Custom radio button to expand the Custom category.

Underneath Choose a default e-mail program, click the radio button next to the program you want to use (e.g. Thunderbird, Windows Live Mail, Outlook).

Click OK at the bottom of the window.

Open the Mail application from the Applications folder.

Click on the Mail menu and select Preferences.

Click General button.

Select a new default mail program (e.g. Thunderbird, Outlook).

Note: These instructions are for some common Linux distributions. Your distribution may use a different interface.

Gnome

Distributions that use the Gnome Desktop Environment by default include Ubuntu, openSUSE, Fedora, Red Hat Enterprise Linux, and more.

Open the Preferred Applications window. The Preferred Applications window can be opened by:

(Ubuntu) Clicking on the System menu, selecting Preferences, and then selecting Preferred Applications.

Clicking on the Applications menu, selecting Desktop Preferences, then selecting Advanced, and then selecting Preferred Applications.

KDE

Distributions that use the K Desktop Environment by default include Kubuntu, Mandriva Linux, PCLinuxOS, and more.

Open the KDE Control Center by clicking on K and selecting Control Center.

In the Control Center window, click to expand KDE Components.

Click to select Component Chooser.

Click to select Email Client.

Click to select the Use a different email client radio button.

Type the full path to your e-mail client (e.g. /usr/bin/thunderbird).

Click Apply to close the Control Center window and save your changes.

Using webmail services

Firefox allows webmail services (such as Gmail, Yahoo! Mail, Hotmail, etc.) to enable you to use them for Firefox's mail functions. Use the instructions in the Setting Firefox's mail client section above to use a webmail service with this method.

Note: Firefox 3.5 and Firefox 3.6 include only Gmail and Yahoo! Mail support by default. You may add other services when they add support for this Firefox feature.

If the webmail service you want to use is not available in the Applications panel of the Options window, you can use an extension to add support to your webmail services: